| 摘要 |
<p>A fluid flow controlling device having independent service passages extending therethrough which provide portions of the service lines leading to a reversible fluid motor from the control valve governing the direction of motor operation. A single fluid pressure actuatable valve element in the device functions as a counterbalance valve and acts to restrict return flow of motor exhaust fluid through either service passage in consequence of decrease in the pressure of source fluid flowing through the other service passage to the motor. Check valves can be located in portions of the service passages so as to be bypassed by return flow of motor exhaust fluid.</p> |
